package offer;

class offer68 {
}
class Solution68 {
    public  static TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) {
    if(root==null) return null;
    if(root.val==p.val||root.val==q.val)
        return root;
        TreeNode left = lowestCommonAncestor(root.left, p, q);
        TreeNode right = lowestCommonAncestor(root.right, p, q);
        if(left!=null&&right!=null)
            return root;
        if(left!=null&&right==null)
            return left;
        if(left==null&&right!=null)
            return right;
        return null;
    }

    public static void main(String[] args) {
       TreeNode root = new TreeNode(1);
        TreeNode node1 = new TreeNode(2);
        TreeNode node2 = new TreeNode(3);
        TreeNode node3 = new TreeNode(4);
        TreeNode node4 = new TreeNode(5);
        TreeNode node5 = new TreeNode(6);
        TreeNode node6 = new TreeNode(7);
        root.left= node1;
        root.right  = node2;
        node1.right = node3;
        node2.left = node4;
        node2.right = node5;
        node3.left = node6;
        lowestCommonAncestor(root,node6,node3);
    }
}